Microwave popcorn fortified with calcium and method of preparation

ABSTRACT

Disclosed are microwave popcorn articles comprising any conventional microwave popcorn bag, and a food charge disposed therein comprising kernel popcorn, fat, salt and sufficient amounts of a calcium ingredient to provide a total calcium content of about 360 to 3600 mg per 100 grams of unpopped popcorn. Preferably the salt and calcium ingredients are essentially characterized by having a mean particle size of less than 25 μm. Methods of preparing such microwave popcorn articles are disclosed wherein some of the salt and/or calcium ingredient is added to the fat slurry while the balance is added in particulate form in a separate step after the fat and kernel popcorn have been added to the bag.

FIELD OF THE INVENTION

The present invention relates to packaged food products. Moreparticularly, the present invention relates to microwave popcorn productarticles characterized by calcium fortification and to methods forfilling such articles.

BACKGROUND

Popcorn is a highly popular snack food item. In the past, the at-homepreparation of popcorn by the consumer involved adding kernel popcornplus a cooking oil to a covered pot and heating until the popcornkernels popped to make popcorn. As used herein, "kernel popcorn" refersto unpopped popcorn. The noun "popcorn" or synonymously "popped popcorn"refers herein to popped kernel popcorn. The adjective "popcorn" canrefer to either. Once prepared, common, relatively coarse, table salt isa frequently added flavoring or condiment. The resultant salted poppedpopcorn is a familiar snack food.

More recently, microwave popcorn products have become extremely popular.At present, in the U.S., over 70 different brands of microwave popcornproducts are available. In general, the more popular microwave popcornproducts comprise an expandable paper bag containing a charge of kernelpopcorn, fat and salt. The microwave popcorn article is adapted to beheated in a microwave oven for three to five minutes to produce thepopped popcorn. More recently, improved microwave popcorn articles havebeen fabricated employing a metallized susceptor which facilitates theheating of the kernel popcorn-fat charge and which, in turn, leadsdesirably to increases in popcorn volume and decreases in unpoppedkernels. Microwave popcorn articles of this type are described in detailin, for example, U.S. Pat. No. 4,450,180 (issued May 22, 1984 to J. D.Watkins and incorporated herein by reference).

Microwave popcorn articles, of course, comprise a microwave popping bagand a charge of kernel popcorn, fat, and, usually, salt. Certain earlypatents taught the addition of kernel popcorn, fat and salt in the formof a prefabricated toroid or doughnut shaped piece. The piece wasfabricated by mixing the kernel popcorn, salt and melted fat to form ablend and the blend was allowed to cool and harden into the toroid shapedesired. These circular pieces were then dropped into the desiredchamber of the popcorn bag prior to final sealing. (See for example U.S.Pat. No. 4,450,180, issued May 22, 1984).

Contemporary methods of filling microwave popcorn bags, however, employa different filling process and technique. (See, for example, U.S. Pat.No. 4,604,854 entitled "Machine For Forming, Filling and Sealing Bags,"issued Aug. 12, 1986 to D. W. Andreas). The microwave bags having anunsealed open end are advanced to a first kernel popcorn fillingstation. While being maintained in an open position, the kernel popcornis charged to the desired channel. Thereafter, the bags are advanced toa second filling station at which the fat/salt slurry is added to thebag. Typically, the slurry is added in the form of a verticallydispensed pencil jet (i.e., a confined stream) of the slurry. Singlestation filling methods are also known that involve applying thefat/salt slurry as a spray onto the kernel popcorn as the kernel popcornfalls into the bag. (See, for example WO 95/01105 entitled "Reduced FatMicrowave Popcorn and Method of Preparation" published Jan. 12, 1995,or, equivalently, U.S. Pat. No. 5,690,979 issued Nov. 25, 1997) which isincorporated herein by reference. Such single station filling techniquesare especially useful for the preparation of low fat microwave popcornproducts.

The bags now containing both kernel popcorn and slurry are then advancedto a sealing station where the bags are provided with a top seal tocomplete the closure of the bag. The sealed popcorn bags are advanced tosubsequent finish packaging operations which complete the folding of thebags, providing the bags with an overwrap, and inserting appropriatenumbers of the bags into cartons, etc.

Thus, while microwave popcorn products are popular, it would bedesirable if such microwave popcorn products were fortified withsupplemental calcium to provide a significantly nutritionally enhancedproduct. By significantly nutritionally enhanced is meant a producthaving at least 10% of the current recommended daily intake ("RDI") orat least 360 mg of calcium (including both the native and supplementalcontributions) per 100 grams of unpopped microwave popcorn.

One conceivable approach is to merely add the calcium along with thesalt to the slurry to facilitate calcium fortification of the foodcharge. However, a first problem can reside in the slurry viscosity. Theslurry viscosity rises rapidly as more particulates are added. If anadditional particulate is desired to be added to the slurry such as forflavor or mineral fortification, then addition of requisite amounts ofsalt to the slurry results in a slurry having a paste consistency and aviscosity too high to pump. This is especially true in the moreconcentrated slurry typically used for ultra low fat popcorn--usuallyabout 94% fat free.

A second problem is plugging of the orifice of the pencil jet nozzleused to charge the slurry to the bag that can occur when the slurryviscosity is too high. While plugging is a problem when salt alone isadded to the slurry, such plugging problems are compounded when theslurry contains supplemental particulates such as a calcium mineral.

Still another problem with adding is that the calcium ingredient is toensure that the calcium ingredient is both visually and organolepticallyindiscernible.

In view of the prior art and the problems described above, there is acontinuing need for new and useful microwave popcorn products thatprovide enhanced nutrition and particularly enhanced calcium levels.Accordingly, it is an object of the present invention to providemicrowave popcorn products having improved mineral nutrient properties.

In particular, it is an object of the present invention to providemethods for preparing calcium fortified microwave popcorn products.

In view of these processing difficulties, a further important object ofthe present invention is to provide for commercially practical methodsfor preparing calcium fortified microwave popcorn products.

Still another object of the present invention is to provide methods forprepared calcium fortified microwave popcorn products wherein thecalcium is supplied by insoluble calcium salts such as calciumcarbonates.

Still another object of the present invention is to provide calciumfortified microwave popcorn having desirable levels of salt.

It has been surprisingly discovered that the above objectives can berealized and superior microwave popcorn products provided by formulatingfood charge compositions disposed with microwave popcorn bags, popcornfat, salt and a calcium ingredient of particular particle size.

It has been surprisingly discovered that the above objectives can berealized and that microwave popcorn articles can be provided thatexhibit novel consumer appeal. In the preferred embodiment, the presentinvention resides in part in the separate, sequential filling of kernelpopcorn, fat and at least a portion of the salt and/or calciumingredient in particulate form at their individual respective fillingstations. By applying the kernel popcorn/fat/salt separately in theparticular sequence in combination with selecting salt and the calciumingredient each of a particular particle size range, improved calciumenriched microwave popcorn articles are achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an unsealed, folded microwave popcornbag.

FIG. 2 is a diagramatic view of one method of filling a microwavepopcorn bag in accordance with the invention.

SUMMARY OF THE INVENTION

In its article aspect, the present invention relates to improvedmicrowave popcorn articles. The present microwave popcorn articlesessentially comprise a microwave popcorn bag and a novel calciumenriched food charge dispersed therein. The calcium enriched food chargeessentially comprises kernel popcorn and optionally further comprisesfat and/or salt. The kernel popcorn component essentially comprisesabout 60 to 97% of the charge. The charge further essentially includessufficient amounts of a calcium source ingredient to provide a totalcalcium content of 360 to 3600 mg per 100 grams of unpopped popcorn. Thetotal calcium content includes both the native level supplied by thepopcorn (and other ingredients) as well as the supplemental addedcalcium.

The food charge can include about 2 to 40% of the fat component andabout 1 to 4% salt. The calcium mineral is essentially characterized bya particle size wherein at least 50% of the calcium component has aparticle size of about 1 to 20 μm.

In its method aspect, the present invention resides in methods forfilling a microwave popcorn bag with popcorn kernels coated with a fatand salt. The salt can be either ultra fine (mean particle size of about20 μm) or coarse salt (mean particle size of about 400 μm).

The present methods of calcium fortified microwave popcorn articlepreparation comprise the steps of:

A. providing a microwave popcorn bag having a sealed bottom end, an opensealable top end defining an upper orifice and a transversely extendingseal area in an open configuration and in a vertically alignedorientation;

B. filling the bag through the upper orifice defined by the open top endwith a quantity of popcorn kernels and the fat slurry;

C. filling the bag through the upper orifice defined by the open top endwith a quantity of a calcium ingredient wherein at least 50% of thecalcium ingredient is in the form of a flour particulate having anaverage particle size of less than 25 microns to provide a total calciumcontent of about 360 to 3600 mg per 100 grams of unpopped popcorn toprovide a calcium fortified food charge; and

D. sealing the open top end of the popcorn bag after the bag has beenfilled with the quantity of popcorn kernels, the fat slurry, and thequantity of calcium ingredient to provide a calcium fortified microwavepopcorn article.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to improved microwave popcorn articlesfortified with calcium and to their methods of preparation. The presentmicrowave popcorn articles essentially comprise a microwave popcorn bagand a food charge disposed within the bag, said food charge comprising aquantity of 1) kernel popcorn, 2) fat, 3) salt, and 4) a calciumingredient. Each of these article components as well as methods offilling, product use and attributes are described in detail below.

Throughout the specification and claims, percentages are by weight andtemperatures in degrees Fahrenheit unless otherwise indicated.

Microwave Bag

The present microwave popcorn articles essentially comprise aconventional microwave popcorn popping bag. Useful herein for themicrowave popping bag are a wide variety of microwave bags availablecommercially or known in the art. Useful microwave bags herein caninclude any conventionally useful bag for microwave popcorn products.

For example, a suitable bag widely used commercially and preferred foruse herein is described in U.S. Pat. No. 4,450,180 patent which isincorporated herein by reference. A generally similar bag is describedin U.S. Pat. No. 4,548,826. Generally, the bag therein describedcomprises and is fabricated from a flexible sheet material having twocollateral tubular sections. The sections are parallel longitudinallyextending that communicate with each other at the center of the package.

Referring now briefly initially to FIG. 1, there is shown an embodimentof a microwave popcorn article 10 composed of a microwave bag 12 formedfrom flexible sheet material such as paper and being of collateraltubular configuration, that is to say, being composed of a pair ofparallel longitudinally extending tubes 14 and 16 which communicate withone another along a central longitudinal opening 18. The two paralleltubes 14 and 16 are separated by longitudinally extending sideindentations 20 and 22. When the package comprises a paper bag, the bagcan be composed of first and second face panels 24 and 26 respectivelyand the indentations 20 and 22 comprises gussets. When in a verticallyaligned orientation, the bag has a bottom seal 28 and initially an opentop or orifice 30 but a sealable seal area 31 that transversely extendsthe open sealable top. The sealable area can include a heat activatedadhesive or a "cold seal" adhesive, as is convenient. After beingfilled, the top 30 is also sealed conventionally by means of heat orother suitable adhesive to provide a top seal in the top seal area 31.

The bag material is generally fabricated with multiple plies includingan outer ply 33 which is generally paper, a grease-proof or resistantinner ply 34 and microwave susceptor film member or ply intermediatethese inner and outer paper layers. However, in preferred embodimentsthe microwave susceptor is present only on one major face panel.

While tubes (or chambers, or channels) 14 and 16 can be of equal size,conventionally the susceptor channel 16 is generally slightly smaller.In such a configuration, the gussets include major left gusset face 36,minor left gusset face 37, major right gusset face 38 and minor rightgusset face 39. The bag 12 can be provided with a lower transverse fold40 to define an intermediate portion or pocket 41.

Although in the present description, a particular description is givento this preferred microwave bag, the present invention is also useful inconnection with, for example, flat bottomed bags, bags with or without abottom fold, with a straight bottom seal or other more complex bottomseal designs. Also, the present methods can be employed using new andimproved microwave popcorn bag designs.

Popcorn

The present article 10 further essentially includes a food chargedisposed within the bag. The food charge essentially includes a quantityof kernel popcorn. Conventionally, microwave popcorn formulations arenow expressed based upon the weight of the entire kernel popcorn and fatfood charge. This convention is followed in the present description ofthe invention. Broadly, the popcorn can range from about 60 to 97% ofthe popcorn charge. Typically, about 15 to 100 g of kernel popcorn isadded to the bag, preferably about 70 to 85 g/bag for regular sizedproducts and about 30 to 50 g/bag for "single portion" sized products.In general practice, the amount of kernel popcorn is set and the otheringredients are varied to provide full fat, reduced or low fat, and/orsalted or low salt embodiments.

Conventional kernel popcorn varieties can be used herein. Highlypreferred for use herein are relatively larger kernel popcorn varieties.Preferred for use herein are those larger varieties having a kernelcount of about 40 to 80 kernels per log, preferably 50 to 65, which arecommercially available.

Fat

The food charge of the present articles additionally essentiallycomprise a quantity of an edible fat. Generally, the present methods areuseful in connection with full fat, reduced-fat and with low-fatembodiments. The present invention finds particular suitability for usein connection with snack products that are perceived as being morehealthy, such as low fat microwave products. Less preferred butnonetheless useful herein are reduced fat or full fat products. Low fatproducts have an even lower fat content than reduced fat embodiments.Reduced fat products have a fat content of about 8 to 15% fat. All fatpercentages are descriptive of added fat and are not meant to includefat which may be included in the finished product from otheringredients, e.g., the fat from the kernel popcorn. Thus, broadly, thefat can range from about 2 to 40% and about 8 to 15%, (most preferably10 to 14%) for reduced fat embodiments. Preferred full fat products cancomprise about 20 to 35% fat. In the low fat embodiments the chargeessentially comprises about 2 to 8% fat, preferably 3 to 4% fat and forbest results about 3.5%.

The fat, preferably semi-solid or solid fat, can be from anyconventional, suitable fat(s) or oil(s) or mixtures thereof fromvegetable or animal sources including from soybean, cottonseed,safflower, corn, peanut oil(s), butter oil and mixtures thereof. Liquidoils (medium chain trigycerides or interesterified oils) can be used infull or in part as a possible variation to reduced trans fatty acidoils. Liquid oils can be thickened to increase their viscosity (e.g.,with silicon dioxide or by being fortified with small amounts of fathardstock). In other variations, the oils can be partially hydrogenated.Preferred for use herein are fats which are partially hydrogenatedsoybean and/or corn oil. Also useful herein are tropical oils such ascoconut oil and palm kernel oil, although present consumer health trendsdisfavor utilization of such oils. Also useful herein are non-absorbablefat mimics such as polyglycerol esters.

In a preferred variation, at least a portion of the fat is supplied by alow moisture butter ingredient. Suitable low moisture butter ingredientsand methods of preparing microwave popcorn products therewith aredescribed in co-pending commonly assigned U.S. Ser. No. 08/784,850(filed Jan. 1, 1997) entitled "Shelf-Stable Butter Containing MicrowavePopcorn" which is incorporated herein by reference. In general, however,the butter ingredients therein described are low moisture (i.e., lessthan 3%) butters that are commercially available. The fat/butter blendscomprise about 200 ppm antioxidants. To assure shelf stability, thebutter content is preferably limited to 10% of the added fat.

Salt

The present microwave popcorn articles additionally essentially includea salt component. Of course, microwave popcorn articles conventionallycomprise a salt component. Typically, the salt component is a microsizedsalt, also known as ultrafine salt or pulverized salt or "flour" salt,typically having a mean particle size of about 22 microns. This floursalt is simply physically admixed in with the fat component to form afat and salt slurry.

In the preferred embodiments, at least a portion of the total salt canbe added in the form of a flour sized particulate to the fat slurry. Inthose embodiments, it is more preferred that the portion of the totalsalt added as a salt flour to the slurry be at least 60% of the totalsalt, even preferably more than 75% of the total salt.

In less preferred variations, a coarse salt ingredient can be employedsuch as described in co-pending commonly assigned U.S. Ser. No.08/998,751, filed Dec. 29, 1997 entitled "Microwave Popcorn With CoarseSalt Crystals and Method of Preparation" (attorney docket 5108) which isincorporated herein by reference. Generally, the coarse salt thereindescribed has a larger particle size of about 250 to 600 μm. Such coarsesalt is added to impart an organoleptic attribute in the finishedproduct microwave popcorn to be more reminiscent of the stove-topat-home popped and seasoned popcorn. While in the preferred embodimentsherein the salt is in flour form, in other embodiments all or a part ofthe salt can be in the form of coarse salt added in the third station orin the separate particulates addition step herein.

Calcium Salt

The present microwave popcorn products essentially further comprise acalcium ingredient of defined particle size in an amount effective toprovide the desired calcium enrichment. Good results are obtained whenthe present microwave popcorn products contain about 360 to 3600 mg per100 grams of the food charge. Better results are obtained when thecalcium is present at levels of about 360 to 1800 mg per 100 grams. Forbest results, the total calcium present ranges from about 930 to 1400 mgper 100 grams of the food charge. Excessive calcium fortification is tobe avoided in part because the finished product can undesirably exhibita dry texture, gritty mouth feel, and lower taste perception of flavorand salt.

At a calcium concentration of 360 to 930 mg per 100 grams of the foodcharge, the finished popped product provides about 10% of the currentlyrecommended daily intake for calcium and thus can be described as "agood source of calcium." The levels in the microwave article suitablefor microwave popping account for an estimated 40% loss factor forcalcium as the popcorn goes from its unpopped state to the popped state.In addition, these levels also reflect the amount consumed based on thecurrent serving size of 30 grams for popped product as defined by theFood and Drug Administration (FDA).

Useful herein are calcium ingredients that supply at least 20% calcium.For example, a good calcium ingredient herein is calcium carbonate inthat calcium carbonate comprises about 40% calcium. While expensive,food grade calcium carbonate obtained by chemical reaction processes isdesirable due to low levels of impurities. A good, inexpensive source ofcalcium carbonate from natural sources is ground limestone. Care shouldbe exercised in selecting sources of ground limestone that are low intrace metals, especially such heavy metals such as lead. In particular,it is desirable that the ground limestone have trace metalconcentrations of less than 10 ppm.

Soluble calcium salts typically are expensive and contain low weightpercentages of calcium. While calcium chloride is an exception to thisgeneralization, addition of significant calcium levels supplied bycalcium chloride impart an unacceptable bitter flavor to microwavepopcorn products. In addition, by adding sufficient amounts of many ofthese calcium salts to achieve the desired fortification level, thefinished product may exhibit an undesirably dry texture and gritty mouthfeel.

Also useful herein are insoluble mineral calcium salts, particularlycalcium phosphate salts provide high levels of calcium and arerelatively inexpensive. Moreover, such calcium phosphate salts can beused to provide calcium at high fortification levels with an acceptabletaste. Calcium phosphate is generally available as a monobasic(CaH4(PO4)2.H2O), dibasic (CaHPO4.2H2O) or tribasic (Ca3(PO4)2) salts.Preferred for use herein is tricalcium phosphate, Ca3(PO4)2, ("TCP")because of its high weight percentage of calcium (about 38%). Moreover,TCP is slightly more soluble than other calcium phosphate salts.

A useful tricalcium phosphate starting material is also known astribasic calcium phosphate or tricalcium orthophosphate and is availablein food chemicals codex grade from Monsanto or Rhone Poulenc, having thegeneral formula 3Ca₃ (PO₄)2.Ca(OH)₂. This product provides an assayedcalcium content of from 34 to 40% by weight. Less preferred butnonetheless useful herein is anhydrous dicalcium phosphate, also knownas anhydrous dibasic calcium phosphate, having a formula of CaHPO₄. Ananhydrous dicalcium phosphate material is also available from Staufferin food chemical codex grade, providing an assay calcium content fromabout 30 to about 31.76 calcium by weight. Other calcium phosphatehydrates also can be useful, including, but not limited to, calciumpyrophosphate, calcium hexametaphosphate and monobasic calciumphosphate.

Phosphate salts are a preferred source of calcium, not only because oftheir acid solubility and weight ratios, but also because they areavailable commercially as a precipitate from whey, a natural dairyproduct.

The skilled artisan will appreciate that while these calcium phosphatesalts are characterized herein as insoluble, of course, some smallpercentage will dissolve in water depending in part upon the temperatureand pH.

Less preferred for use herein but nonetheless useful are other organiccalcium salts including calcium ascorbate, calcium citrate, calciumgluconate, calcium lactate, and calcium sulfate. Also useful herein arethe calcium citrate malate complexes described in U.S. Pat. No.5,186,965 entitled "Calcium Citrate Malate Compositions" (Feb. 16, 1993)which is incorporated herein by reference. Such organic calcium saltsare less preferred primarily based upon cost considerations.

Preferred for use herein are calcium ingredients selected from the groupconsisting of food grade calcium carbonate, ground limestone, calciumphosphate salts and mixtures thereof.

The calcium ingredient regardless of source or type is furtheressentially characterized by a particularly fine particle size. Such afine or flour form of the calcium ingredient provides a particle sizesuch that the average particle size is less than 25 μm.

Even more preferred for use herein are calcium ingredients having a meanparticle of less than 15 μm and for best results less than 10 μm. A goodmaterial, for example, is a ground limestone of high purity having anaverage particle size of 3.8 μm available from Pluess-Stauffer(California), Inc. (Lucerne Valley, Calif.).

Optional Ingredients

While in the preferred embodiment the particulate addition in the thirdor separate particulate addition step after the slurry has been added isa calcium ingredient, the skilled artisan will appreciate that otherparticulates can be conveniently added in the third filling station orin this step. Such additional particulates can include a wide variety ofmaterials intended to provide various flavor or nutritional advantages.Such materials include sugars, dried dairy ingredients such as driedcheese solids, other minerals, magnesium oxide and mixtures thereof.

However, in more preferred embodiments, the present microwave productsare additionally characterized as being sugar free (i.e., by total mono-or disaccharide content of less than 0.5%). Such products exhibitgreater shelf stability as well as minimization of sugar relatedscorching and burning.

In other more preferred embodiments, the present microwave products areadditionally characterized as being free of a cheese constituent (i.e.,having a cheese ingredient content of less than 0.5%, dry weight basis).Cheese ingredients can also undesirably contribute to scorching andburning problems in microwave popcorn products. It is believed thatthese problems are due to the protein and sugar (e.g., lactose)constituents thereof. Thus, dried cheeses being generally low in fat andthus high in other constituents are particularly undesirable.

In highly preferred embodiments, the present articles are both sugar(s)free and cheese ingredient free.

Method of Preparation

Now referring to FIG. 2, there is seen a schematic of the method ofpreparation preferred for use herein generally designated by referencenumeral 50. The drawing shows a conventional microwave packaging lineand depicts three stations thereof designated generally by referencenumbers 51, 52 and 53. In upstream stations, (not shown) the tubular bagmaterial is cut into desired lengths, and is provided with the bottomseal 28. Additionally, in upstream stations (not depicted), the bags 12are folded to have their bottom third folded up as depicted in firststation 51 of FIG. 2 to provide the first lower transverse fold 40 toprovide a sealed portion so that the kernel popcorn, fat charge, andcoarse particulate salt can be positioned within the bag in the desiredmiddle portion 41 thereof. The bags 12 are advanced from station tostation (left to right) by suitable drive means such as the endlessdrive chain 54 depicted having bag engagement clips 55. Packaging linespeeds range from about 50 to 100 bags per minute. Also, the bottomthird of the bags are maintained in the closed position by appropriatelyspaced parallel guide bars 56 and 58. As can be seen, the bag has anopen sealable top portion defining an orifice and has a seal areaextending across the orifice. The bag at station 51 is provided in anopen configuration and in a vertically aligned orientation.

In the present preferred method of filling microwave popcorn bags, thefirst station 51 is a popcorn filling station. The fat addition ischarged to the bag at a second separate station 52.

Thereafter, the bags being maintained in the upright, folded orientationdepicted in FIG. 2 are advanced to the third particulate filling station53. At the particulate filling station, a quantity of a particulate isthen charged to the bag 12 in a separate step.

Once filled with the popcorn, fat slurry and particulate, the bags arethen advanced to the sealing station (not shown) wherein the open topend is sealed such as by retractable heat or pressure sealing jaws whichimpart a seal in the seal area.

The filled and sealed microwave popcorn bags are then advanced tosubsequent downstream packaging operations (not shown). Such subsequentdownstream packaging operations include folding the bags again toprovide a three-folded bag, i.e., to provide a second upper transversefold; overwrapping the folded bags with an overwrap or moisture barrierlayer; and inserting desired numbers of the packaged article intocartons.

Now that the present methods have been described in general terms, inparticular, at the filling station 51 the process involves the step 62of filling the bag through the upper orifice with a quantity of popcornkernels. Generally, however, the process step can conveniently bepracticed at filling station 51 by employing a means for dispensing ameasured quantity of kernel popcorn such as a dispensing wheel. Thedispensing wheel discharges at timed intervals a measured quantity(e.g., 80 to 90 g) of the kernel popcorn into a vertically orientedfilling horn or funnel. The funnel causes the kernel popcorn to fall bygravity into the bag 12.

At the second or fat slurry filling station 52, the present methodsadditionally include the step 64 of filling the bag 12 through the upperorifice with a quantity of fat (with or without butter).

The term slurry is used herein as is common in the microwave popcorn artto refer to any coating applied to the kernel popcorn. The term "slurry"as used generally herein thus includes fat alone; fat and a lesserportion of salt in flour form; fat, flour salt, flavors and/or color orsweetener(s); fat, a portion of the flour salt and a portion of thecalcium ingredient; and fat and substantially all of the calciumingredient as well as any other variation or combination of ingredientsused as an addition to the kernel popcorn herein.

The slurry can additionally optionally comprise minor amounts of othermaterials employed to make the microwave popcorn more aesthetically ornutritionally or organoleptically appealing. Such adjuvant ingredientscan include, for example, sugar(s), minerals, vitamins, colorants,preservatives and flavors. If present, each of these constituents cancomprise from about 0.01 to about 2% (or more for sugar, cheese solids)by weight of the fat slurry.

Especially popular for use herein is a butter flavor. The flavors can beeither in liquid, fat soluble forms and/or in dry powder forms such as aliquid oil absorbed onto a particulate carrier, e.g., gum arabic,starch, silicon dioxide, or dehydrated cheese solids.

The fat slurry is prepared simply by admixing the fat (in a fluid ormelted state) together with any optional ingredients with salt andblending the mixture to form a stable dispersion or slurry. The fat orslurry, while still fluid (70° to 130° F.; 21° to 55° C.), is thensprayed into the microwave popcorn bag as described in detail below.

The slurry application step can be practiced by employing an applicatorfor spraying the fat slurry (e.g., commercially available from HibarSystems Limited, Ontario, Canada) that is supplied by a slurry supplymeans (not shown). The slurry supply means can conveniently include aconventional positive displacement reciprocating metering pump having apiston and a pressurized slurry inlet. The pump precisely pumps meteredamounts of the fat slurry to the applicator at closely controllable timeintervals.

If the slurry viscosity is too high, then the slurry becomes unpumpable.The concentrations of salt and calcium ingredients are selected suchthat the slurry has a viscosity of less than 10,000 cps, preferably lessthan about 4,000 cps, and, for best results, less than 1,000 cps.

The slurry can be added at temperatures ranging from about 15.5° to65.5° C. (60° to 150° F.), preferably about 21.1° to 54.4° C. (70° to130° F.)

While a pencil jet spray is preferred for use herein, equivalentsthereof in terms of dispensing the slurry can also be used. For example,a multiplicity of very fine jet streams, (e.g., 3-12), or a sparge canbe used to achieve the desired dispersion hereunder. Also, other spraytypes, (e.g., a cone spray, a mist spray, or a fan spray) are usefulherein. However, great care must be taken in selecting such usefulalternatives so as to avoid getting slurry in the bag seal area. Inother embodiments, the spray can be gas assisted, e.g., air, steam, orinert gas.

In preferred embodiments, the bag 12 has a microwave chamber (i.e.,wherein one major face panel has an intermediate microwave susceptorlayer between the inner and outer bag layers) and, for costconsiderations, a microwave susceptor-free chamber. In the preferredpractice, the kernel popcorn, fat slurry and particulate(s) are chargedto the microwave channel. Conventionally, the microwave channel is thelesser channel (i.e., being formed by the smaller major face 24) and thegreater channel is the microwave free channel. Such a configurationminimizes the amount of relatively expensive microwave susceptormaterial required while nonetheless providing the needed expansionvolume upon microwave popping.

In the preferred form, the popcorn charging and slurry addition arepracticed at separate stations and as separate steps. However, in otherembodiments, the kernel popcorn and slurry addition can be practiced ina single station concurrently. Apparatus and techniques for suchconcurrent filling of the popcorn and slurry are described in commonlyassigned U.S. Pat. No. 5,690,979 (issued Nov. 25, 1997) entitled "Methodof Preparing Reduced Fat Microwave Popcorn."

At station 53, it can be seen that the present methods additionallycomprise the step 66 of filling the bag with a quantity of a particulateafter the bag is filled with popcorn and fat.

Generally, however, the particulate filling station 53 includes a meansfor dispensing a measured quantity of salt, calcium ingredient(s), otherparticulates and mixtures thereof.

If high levels of salt and calcium ingredients are desired in thefinished products, addition of the total quantity of each of thesematerials to the slurry will cause the slurry viscosity to beexcessively high. That is, while the slurry may be able to carry all ofthe salt or all of the calcium ingredient, or half of each, the slurrycannot carry all of both. Thus, either all of the salt or all of thecalcium ingredient or a portion of each (e.g., 50:50 or 70:30) must beadded as dry particulates in the third filling station or in the presentessential particulates addition step. Useful herein for practicing thisstep are particulate metered feeding equipment that are commerciallyavailable such as are used for filling salt or sugar packets.

The present methods further essentially include a conventional finishstep (not shown in FIG. 2) of sealing the open end of the microwavepopcorn bag after the bag has been filled with the quantity of popcornkernels, the fat slurry and the quantity of particulates.

Product Use

The microwave popcorn products prepared as described can be used in aconventional manner for the at-home preparation of popcorn by microwaveheating. Upon microwave heating of the sealed microwave popcorn articlein a conventional home microwave oven, the resultant popped popcorn inthe form of free flowing of individual substantially unagglomeratedpopped popcorn kernels exhibits excellent organoleptic attributesnotwithstanding the calcium fortification. Regrettably, up to about 40%of the added calcium is lost within the microwave popcorn bag and doesnot adhere to the popped popcorn.

Industrial Applicability

The present invention finds suitability for use in the provision of amass market, shelf stable consumer food item adapted to prepare oiled,flavored popcorn upon microwave heating that is calcium fortified to atleast 0.03% calcium.

Without further elaboration, it is believed that one skilled in the artcan, using the preceding description, utilize the present invention toits fullest extent. The following preferred specific embodiments are,therefore, to be construed as merely illustrative and not limitative ofthe remainder of the disclosure. It will be appreciated that othermodifications of the present invention, within the skill of themicrowave popcorn art, can be undertaken without departing from thespirit and scope of the invention.

EXAMPLE 1

An improved microwave popcorn article of the present inventioncomprising a microwave popcorn bag is prepared having the popcorn/fatcharge of the composition indicated below. The microwave popcorn bag isfabricated substantially in accordance with the teachings of U.S Pat.No. 4,450,180. Microwave popcorn articles comprising microwave popcornbags of this type are available under the brand name Betty Crocker™/PopSecret™. The popcorn fat charge has the following composition:

    ______________________________________                                        Ingredients      Weight %                                                     ______________________________________                                        Popcorn          92.1                                                         Fat.sup.1        2.4                                                          Salt             2.7                                                          CaCO.sub.2.sup.2 2.5                                                          Artificial butter flavor                                                                       0.3                                                                           100.0                                                        ______________________________________                                         .sup.1 A hydrogenated soybean oil available from Cargill Foods under the      trade name 600S.                                                              .sup.2 Pure calcium carbonate available from Specialty Minerals Inc.          having a mean particle size of 3 μm.                                  

A supply of the fat, butter, salt and CaCO₂ is prepared to form a warmslurry (about 122° F.; 50° C.). The slurry has a viscosity of 3500 cps.

The fat slurry comprises:

    ______________________________________                                                Fat   44.5%                                                                   Salt  25.7%                                                                   CaCO.sub.2                                                                          6.2%                                                                    Butter                                                                              23.6%                                                           ______________________________________                                    

Thus, the slurry has about 50% of the total salt and about 50% of thecalcium carbonate. The calcium carbonate had a particle size of lessthan 25 μm.

The salt added to the slurry was a flour salt having a mean particlesize of about 22 μm.

A quantity of microwave popcorn bags were filled as follows:

About 82 g of popcorn was dispensed by the dispensing wheel into thefunnel.

The popcorn filled bag was then advanced to a second filling station. Afat slurry applicator was timed to dispense about 4.79 of the slurry inthe form of a downwardly projecting vertically aligned pencil jet spray.The duration of the spray was about 0.5 seconds. The slurry charged thefat slurry within the microwave popcorn bag below the seal area.

The popcorn and fat filled bags were then advanced to a third fillingstation. About 1.2 g of salt were dropped by gravity into the open endof the bag. At the same time about 1 g of the CaCO₂ was dropped. TheCaCO₂ was in flour form having a mean particle size of about 5.7 μm.

The bags were then heat sealed to form finished full fat microwavepopcorn articles of the present invention. The articles can be furtherprovided with a conventional moisture resistant overwrap (e.g.,fabricated from polypropylene material). The microwave popcorn articlesso prepared can be conventionally microwave heated to provide poppedpopcorn having high levels of calcium. Notwithstanding the high calciumfortification levels (20% of the Recommended Daily Intake (RDI)), thepopped popcorn is neither visually nor organoleptically discerniblydifferent from conventionally prepared microwave popcorn.

Reduced fat and full fat microwave products of the present invention canbe prepared wherein in the Example the fat and butter content areadjusted in amount.

Substantially equivalent microwave popcorn articles of the presentinvention are prepared when the pure calcium carbonate calciumingredient of the above example is substituted with ground limestone ofsimilar particle size.

What is claimed is:
 1. A method for filling a microwave popcorn bag witha food charge of popcorn kernels, a fat slurry, and a particulate,comprising the steps of:A. providing a microwave popcorn bag having asealed portion, an open sealable top portion defining and orifice and aseal area extending across the orifice in an open configuration and in avertically aligned orientation; B. filling the bag through the upperorifice with a quantity of popcorn kernels and the fat slurry; C.filling the bag through the upper orifice with a quantity of aparticulate after the bag is filled with the popcorn kernels and the fatslurry, wherein at least one of the fat slurry and the particulateincludes a calcium ingredient; and D. sealing the open top end of thepopcorn bag after the bag has been filled with the quantity of popcornkernels, the fat slurry, and the quantity of particulate.
 2. The methodof claim 1 wherein the step of filling the bag with the quantity ofpopcorn kernels and the fat slurry comprises the substeps of:1.dispensing the quantity of popcorn kernels in an airborne stream; andconcurrently,
 2. spraying a quantity of the fat slurry into the airbornepopcorn stream to coat the popcorn with the slurry.
 3. The method ofclaim 1 wherein the step of filling the bag with the quantity of popcornkernels and the fat slurry comprises the substeps of:1. dispensing thequantity of popcorn kernels through the upper orifice; and
 2. spraying aquantity of fat slurry through the upper orifice defined by the open topend.
 4. The method of claim 3 wherein the spraying step is after thedispensing step.
 5. The method of claim 4 wherein in step C theparticulate includes the calcium ingredient which has a mean particle ofless than 25 microns.
 6. The method of claim 4 wherein the fat slurryincludes the calcium ingredient which has a particle size of less than25 microns.
 7. The method of claim 5 wherein the particulate furtherincludes a salt in flour form having a particle size of less than 90microns.
 8. The method of claim 7 wherein the food charge comprisesabout 50 to 97% popcorn, about 2 to 40% fat and about 1 to 4% salt,sufficient amounts of the calcium ingredient to provide the food chargewith a total calcium content of about 360 to 3600 grams per 100 grams ofunpopped popcorn.
 9. The method of claim 8 wherein the fat includes atleast 50% of the calcium ingredient in flour form having a mean particlesize of less than 15 microns.
 10. The method of claim 9 wherein at leasta portion of the fat is supplied by a low moisture butter.
 11. Themethod of claim 10 wherein the fat includes about 200 ppm ofantioxidant.
 12. The method of claim 11 wherein the particulate includesat least a portion of the salt in coarse form having a particle size ofabout 250 to 600 microns.
 13. The method of claim 11 wherein the foodcharge is free of a cheese ingredient.
 14. The method of claim 13wherein the fat or slurry has a spray temperature of between about 70°to 130° F. (21° to 54.5° C.) and the fat is a material selected from thegroup consisting of low melting point fats, partially hydrogenated oils,fluid fats, and mixtures thereof.
 15. The method of claim 14 wherein thefood charge is free of added sugar(s).
 16. The method of claim 15wherein the food charge contains sufficient amounts of the calciumingredient to provide about 360 to 1800 mg per 100 grams of unpoppedpopcorn.
 17. The method of claim 16 wherein the calcium ingredient isselected from the group consisting of pure calcium carbonate, groundlimestone, calcium phosphate salts, and mixtures thereof.
 18. The methodof claim 17 wherein at least a portion of the calcium ingredient isground limestone.
 19. The method of claim 15 wherein the popcornquantity ranges from about 59 to 79% and the fat quantity ranges fromabout 20 to 40%.
 20. A microwave popcorn article exhibiting desirableorganoleptic attributes comprising:a continuously sealed microwavepopcorn bag, and a food charge disposed therein of popcorn and fatuniformly dispersed upon the popcorn, said charge comprising:A. about 50to 98% of the product of unpopped popcorn kernels, B. about 2 to 40% ofthe product of an edible fat uniformly dispersed upon the popcornkernels, C. about 1 to 46 of the product of salt at least 60% of whichhaving a mean particle size of less than 25 microns, and D. sufficientamounts of a calcium ingredient to provide a total calcium content ofabout 360 to 3600 mg per 100 grams of unpopped popcorn.
 21. The articleof claim 20 wherein the calcium ingredient has a mean particle size ofless than 25 microns.
 22. The article of claim 21 wherein at least aportion of the calcium ingredient is supplied by a member selected fromthe group consisting of pure calcium carbonate, ground limestone,calcium phosphate salts, and mixtures thereof.
 23. The article of claim22 wherein at least 60% of the salt is supplied by a flour salt havingan average particle size of less than 50 microns.
 24. The article ofclaim 23 wherein the food charge is free of a cheese ingredient.
 25. Thearticle of claim 24 wherein the food charge is free of sugar.
 26. Thearticle of claim 25 wherein the edible fat is a material selected fromthe group consisting of low melting point fats, partially hydrogenatedoils, fluid fats, and mixtures thereof.
 27. The article of claim 26wherein at least a portion of the calcium ingredient has a mean particlesize of less than 15 microns.
 28. The article of claim 26 wherein atleast a portion of the calcium ingredient is pure calcium carbonate orground limestone.
 29. The article of claim 28 wherein at least a portionof the calcium ingredient is supplied by ground limestone.
 30. Thearticle of claim 29 having about 70 to 85 g popcorn.
 31. The productprepared by the process of claim
 1. 32. The product prepared by theprocess of claim
 2. 33. The product prepared by the process of claim 3.34. The product prepared by the process of claim 5, andwherein thepopcorn has a kernel count of about 40 to 80 per 10 g.
 35. In amicrowave popcorn article comprising a sealed microwave popcorn bag anda food charge disposed within the bag comprising popcorn, fat and salt,the improvement comprising: fortifying the food charge with a calciumingredient in amounts sufficient to provide 360 to 3600 mg per 100 gramsof unpopped popcorn, andwherein the calcium ingredient has a meanparticle size of less than 25 μm.
 36. The microwave popcorn article ofclaim 35 wherein the calcium ingredient has a mean particle size of lessthan 15 μm.
 37. The microwave popcorn article of claim 36 wherein thecalcium ingredient includes a member selected from the group consistingof precipitated calcium carbonate, ground limestone, calcium phosphatesalts and mixtures thereof.
 38. The microwave popcorn article of claim37 additionally comprising a moisture barrier overlap.
 39. The microwavepopcorn article of claim 38 wherein at least a portion of the calciumingredient is provided by ground limestone.